1. Field of the Invention
The present invention relates to a microorganism of Corynebacterium genus having enhanced L-lysine production ability and a method of producing L-lysine using the same.
2. Description of the Related Art
Microorganisms of Corynebacterium genus, particularly Corynebacterium glutamicum are gram-positive microorganisms that are used in L-amino acid production. L-amino acid, particularly L-lysine is widely used for animal feed and medical supplies, and is produced by fermentation of the microorganisms of Corynebacterium genus. As such, the microorganisms of Corynebacterium genus are important in producing L-amino acid, and thus much research on improving the method of producing L-amino acid has been conducted.
This research includes a method of developing microorganisms of Corynebacterium genus that produces L-amino acid by disrupting specific genes or attenuation expressing specific genes using recombination DNA technique. For example, U.S. Pat. No. 6,872,553 discloses a method of producing L-lysine of microorganisms of Corynebacterium genus by fermentation. The method comprises: growing microorganisms of Corynebacterium genus having an attenuated DNA encoding phosphoenol pyruvate (PEP) carboxykinase (pck) by at least one mutation selected from the group consisting of insertion mutation in which at least one base pair is inserted into the DNA, deletion mutation in which at least one base pair is deleted from the sequence of the DNA, base pair transition and transversion mutation introducing a nonsense codon in the DNA or having reduced phosphoenol pyruvate (PEP) carboxykinase (pck) activity compared with microorganisms of Corynebacterium genus that are not attenuated; concentrating desired L-amino acid product in medium or cells of the microorganism; and separating the L-amino acid.
In addition, many studies on how each gene involved in L-amino acid biosynthesis affects L-amino acid production by amplifying the genes to develop microorganisms of Corynebacterium genus have been conducted (Eggeling, Amino Acids 6, 261-272 (1994)). Also, microorganisms of Corynebacterium genus can be developed by introducing foreign genes from other bacteria. For example, Japanese Patent Publication No. hei 7-121228 discloses a method of producing L-glutamine acid and L-proline acid. The method comprises culturing microorganisms of Corynebacterium genus or Brevibacterium genus that contain recombinant construct between DNA fragment having genetic information involving synthesis of citric acid synthase and vector DNA, and producing L-glutamine acid and L-proline acid from the cultures.
However, demand for microorganisms having improved L-lysine production ability still exists.